Every year, residential construction workers experience numerous fatal injuries due to
falls. Installing roof trusses presents several challenges for protecting workers from
these falls. This fact sheet highlights some of the hazards of truss installation and lists
some practical methods that employers can use to protect workers who install trusses.

Risks During Truss Installation

Accidental falls are the leading cause of death for
construction workers and installing roof trusses
can be particularly dangerous for two reasons: (1)
truss construction usually occurs high above the
ground and (2) trusses are not stable until they
are properly restrained and braced.

Roof trusses are the highest part of a house
frame, so residential construction workers
installing them can fall and be seriously injured or
even killed. Although personal fall arrest systems
(PFAS) are the most widely used form of fall
protection in residential construction, they might
not be suitable when workers begin installing roof
truss sections because there may not be a stable
place to attach an anchor. Trusses are designed to
support weight from the top down. Until trusses
are properly restrained and braced, they are weak
if pulled from the side (i.e., subjected to lateral
force) as can occur when a truss-mounted fall
protection system bears the full weight of a falling
worker.

PFAS need strong anchor points that can hold the
sudden weight of a falling worker. No anchor with
a single connection point, such as a strap anchor
or a bolt-on anchor, will protect a falling worker
who is attached to a single truss.

Other systems, such as scaffolds, lifts and ladders
can be used to protect workers until a fully interconnected,
multi-truss section has been appropriately
braced and secured.

OSHA requires fall protection measures for residential
construction activities 6 feet or more
above lower levels. As a result, employers must
plan ahead to ensure they have the right systems
in place, and that all workers are properly trained
before the job begins.

Personal Fall Arrest System (PFAS)

A PFAS is designed to safely stop a fall before the
worker strikes a lower level. It includes three
major components:

An anchorage to which the other components
of the PFAS are rigged.

A full body harness worn by the worker.

A connector, such as a lanyard or lifeline, linking
the harness to the anchorage. A rip-stitch
lanyard, or deceleration device, is typically a
part of the system.

For more information on the requirements for a
PFAS, refer to 29 CFR 1926.502(d).

Remember that for fall arrest systems, workers
must use full-body harnesses. Body belts can
cause serious injury during a fall and so OSHA
prohibits their use as part of fall arrest systems.

If a worker falls while using a single truss as an anchor point, the whole truss assembly can collapse. Such a structural failure puts workers’ lives and entire buildings at risk.

How to Reduce Risks

During Initial Truss Installation

Guardrails, nets, or PFAS (conventional fall
protection) may not be practical for all phases of
truss installation. Instead, employers should plan
to use other methods, such as ground assembly,
scaffolds, aerial lifts, or ladders to keep workers
safe.

Ground assembly: By assembling a truss section
on the ground, employers can greatly reduce the
risk of falls for workers. A section of trusses can
be sheathed while still on the ground. Peak
anchors and lifelines can be pre-installed before
the section is lifted into place. Many builders find
it efficient to pre-assemble truss sections on the
ground and then lift them with a crane so that
workers can secure the section to the building
frame.

Lifts: Depending on the building layout and the
tasks involved, lifts (e.g., aerial, scissor) may be
options for setting trusses. Lifts provide a stable,
elevated platform from which workers can operate.
Workers must follow all safety procedures
and conduct all operations from inside the lift
basket. For other requirements for using lifts,
refer to 29 CFR 1926.453, Aerial Lifts.

Scaffolds: When properly constructed and used,
internal and external scaffolds can provide suitable
protection for truss-setting tasks. For example,
bracket scaffolds placed on the inside or outside
of a building provide large, stable walking
and working areas for workers. To ensure safe use
and appropriate load limits for bracket scaffold
systems, workers should always follow the manufacturer’s
instructions or consult a qualified person.
For other requirements for scaffolds, refer to
29 CFR 1926 Subpart L, Scaffolds.

Ladders: For certain truss-setting jobs, platform
and stepladders can provide a stable work platform
for workers. They can be particularly helpful
when set up inside a building. Workers should
always use a ladder safely by following the
requirements spelled out in 29 CFR 1926 Subpart
X, Stairways and Ladders.

Spreader: An engineered spreader, when installed
in accordance with the manufacturer’s instructions,
distributes the force of a PFAS across multiple
trusses. The roof trusses do not need to be
sheathed to use a spreader. These engineered
anchorage devices are reusable and can be uninstalled
and reinstalled quickly. A qualified person
should decide if the spreader is suitable for use as
an anchor.

After a Complete Truss Section Is Fully
Installed

Once the assembled truss section has been set
and secured, it can be used as an attachment
point for an anchorage device. From this point on,
PFAS can be used to protect workers while they
install additional trusses and roof sheathing.

Truss Section

Multiple (typically four) individual trusses that
are interconnected and fully sheathed. A truss
section that has been restrained, braced and
sheathed in accordance with the manufacturer’s
instructions can provide a suitable structure to
establish an anchor point.

Anchors: Fixed anchors provide a secure point
where workers can tie off their lifelines as part of
a PFAS. Anchors for a PFAS must meet the 5,000-
pound strength requirement or maintain a safety
factor of at least two under the supervision of a
qualified person – 29 CFR 1926.502(d)(15). See 29 CFR 1926 Subpart M, Fall Protection for more
information and additional requirements.

Different types of anchors for these systems
include, but are not limited to:

Peak anchors

Strap anchors

Bolt-on anchors

Once a group of trusses has been properly
restrained and braced, a roof peak anchor can provide
a usable tie-off point for a lifeline. Multiple
peak anchors and lifelines can protect several
workers. After confirmation from the manufacturer,
some peak anchors may be strong enough to
serve as tie-off points for two lifelines. Peak
anchors can also be useful for fall protection during
later roofing tasks or while setting another
truss section.

Written Fall Protection Plans

If the employer does not use ladders, scaffolds,
or aerial lifts, and can demonstrate that it is not
feasible or would create a greater hazard to use
conventional fall protection equipment (guardrails,
safety nets, or PFAS) when working at heights of
6 feet or greater, the employer must develop a
written site-specific fall protection plan in accord
with 29 CFR 1926.502(k). The plan must be
prepared by a qualified person as defined by 29
CFR 1926.32(m). This person could be the owner,
the supervisor, or a worker who has extensive
knowledge, training and experience with fall protection
and is able to solve problems relating to
fall protection. States with OSHA-approved State
Plans may have additional requirements for
written fall protection plans.

The site-specific fall protection plan must
document at each location why the use of
conventional fall protection equipment is not
feasible or will create a greater hazard. The plan
must also describe the alternative methods that
the employer will use so that workers are
protected from falls. Workers and their
supervisors must be trained on the proper use
of those other fall protection methods.

Conventional fall protection equipment can reduce
or eliminate the chances of a fatal fall. Written sitespecific
fall protection plans ensure that protection
continues, even when conventional fall protection
methods are determined to not be feasible.

OSHA Compliance Guidance:

State Plan Guidance: Twenty-seven states or
territories currently operate their own OSHAapproved
state plans. State plan workplace
health and safety standards must be at least as
effective as comparable Federal OSHA standards.
State plans have the option of promulgating
more stringent standards and, therefore, may
have additional requirements for residential construction. For more information on state plans
and their requirements, please visit:
www.osha.gov/dcsp/osp/statestandards.html.

Help for Employers: OSHA's On-site Consultation
Program offers free and confidential advice to
small and medium-sized businesses in all states
across the country, with priority given to highhazard
worksites. On-site Consultation services
are separate from enforcement and do not result
in penalties or citations. Consultants from state
agencies or universities work with employers to
identify workplace hazards, provide advice on
compliance with OSHA standards and assist in
establishing injury and illness prevention
programs. To locate the OSHA Consultation
Program nearest you, call 1-800-321-OSHA (6742)
or visit www.osha.gov/dcsp/smallbusiness/consult.html.

NIOSH Prevention Through Design
Program

This is one in a series of informational fact sheets highlighting OSHA programs, policies or standards. It does not impose any new compliance requirements. For a comprehensive list of compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal Regulations. This information will be made available to sensory-impaired individuals upon request. The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

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